Stabilization of polyolefins with liquid cyclic phosphites

Abstract

The present invention discloses liquid cyclic phosphites of for example the formula where n is 1 or 2; when n is 1, R 17 is straight or branched chain alkyl of 1 to 18 carbon atoms, when n is 2, R 17 is —C t H 2t — or —CH 2 CH 2 -T 3 -CH 2 CH 2 — where T 3 is —S— or >N—R 22 where R 22 is straight or branched chain alkyl of 1 to 12 carbon atoms and t is an integer of from 2 to 6, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently hydrogen, methyl, ethyl, i-propyl, n-propyl, n-butyl, sec-butyl or t-butyl and R is hydrogen. Also disclosed is a stabilized composition comprising polyolefin and a present liquid cyclic phosphite and a process for the stabilization of polyolefin by incorporating therein or applying thereto a present liquid cyclic phosphite. The present liquid phosphite stabilizers are especially compatible with polyolefins.

1 . A compound of the formula I or II  
     
       
         
         
             
             
         
       
     
     wherein 
 R is hydrogen or methyl,  
 R 1 , R 2 , R 3 , R 4 , R 5  and R 6  are independently hydrogen, straight or branched chain alkyl of 1 to 24 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 9 carbon atoms, said phenylalkyl substituted on the phenyl ring by one or two straight or branched chain alkyl of 1 to 12 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one or two straight or branched chain alkyl of 1 to 12 carbon atoms, or  
 R 1  and R 2  together, or R 3  and R 4  together, or R 5  and R 6  together, or one of R 1  or R 2  together with one of R 3  or R 4 , or one of R 3  or R 4  together with one of R 5  or R 6 , with the ring carbon atoms to which they are attached form a cycloalkyl ring of 5 or 6 carbon atoms,  
 X and Y are independently —O—, >N—R 22  or —S—,  
                     
 where * denotes the point of attachment,  
 which cyclic phosphites are in the liquid state at 25° C. and 1 atm of pressure.  
 
   
   
       2 . A compound of the formula I according to  claim 1 .  
   
   
       3 . A compound of the formula II according to  claim 1 .  
   
   
       4 . A compound of the formula I according to  claim 1 , 
 where    X and Y are —O—,    n is 1,    R 17  is straight or branched chain alkyl of 1 to 18 carbon atoms,    R 1 , R 2 , R 3 , R 4 , R 5  and R 6  are independently hydrogen or straight or branched chain alkyl of 1 to 20 carbon atoms and    R is hydrogen.    
   
   
       5 . A compound of the formula I according to  claim 1 , 
 where    R 22  is straight or branched chain alkyl of 1 to 18 carbon atoms,    n is an integer from 1 to 4,    if n=1    R 17  is hydrogen, straight or branched chain alkyl of 1 to 24 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, or R 17  is —CH 2 CH 2 -T 3 -R 19  or —(C r H 2r O) p —C r H 2r OR 19  where T 3  is —O—, —S— or >N—R 2 , R 22  is straight or branched chain alkyl of 1 to 18 carbon atoms, R 19  is straight or branched chain alkyl of 1 to 18 carbon atoms, p is an integer from 1 to 20 and r is 2 or 3,    if n=2    R 17  is a divalent radical —C t H 2t — or —(C r H 2r O) p —C r H 2r — where t is an integer of from 2 to 16, p is an integer from 1 to 20 and r is 2 or 3, or R 17  is a divalent radical —CH 2 CH 2 -T 3 -CH 2 CH 2 — or —CH 2 —CH═CH—CH 2 — where T 3  is —O—, —S— or >N—R 22  where R 22  is straight or branched chain alkyl of 1 to 18 carbon atoms,    if n=3    R 17  is a trivalent radical                          where R 27  is hydrogen or straight or branched chain alkyl of 1 to 4 carbon atoms and where * denotes the point of attachment and    if n=4    R 17  is an alkanetetrayl of 4 to 12 carbon atoms or is    X and Y are —,    n is 1,    R 17  is straight or branched chain alkyl of 1 to 18 carbon atoms,    R 1 , R 2 , R 5  and R 6  are independently hydrogen or methyl and R 3  and R 4  are independently methyl, ethyl, i-propyl, n-propyl, n-butyl, sec-butyl or t-butyl and    R is hydrogen.    
   
   
       6 . A compound of the formula I according to  claim 1 , 
 where    X and Y are —O—,    n is 2,    R 17  is —C t H 2t — or —CH 2 CH 2 -T 3 -CH 2 CH 2 — where T 3  is —S— or >N—R 22  where R 22  is straight or branched chain alkyl of 1 to 12 carbon atoms and t is an integer of from 2 to 6,    R 1 , R 2 , R 5  and R 6  are independently hydrogen or methyl and R 3  and R 4  are independently methyl, ethyl, i-propyl, n-propyl, n-butyl, sec-butyl or t-butyl and    R is hydrogen.    
   
   
       7 . A compound of the formula I according to  claim 1  selected from the group consisting of  
     
       
         
         
             
             
         
       
     
   
   
       8 . A compound of the formula I or II according to  claim 1  where the compound exhibits a viscosity of less than about 1000 mPa·sec at 20° C. or less than about 150 mPa·s at 40° C. as measured on a cone/plate rheometer: 40 mm 2° steel cone with peltier plate, constant 10 Pa shear stress, 2° C./min temperature ramp from 0° C. to 100° C.  
   
   
       9 . A compound of the formula I or II according to  claim 1  where the compound exhibits a viscosity of less than about 750 mPa·sec at 20° C. or less than about 135 mPa·s at 40° C. as measured on a cone/plate rheometer: 40 mm 2° steel cone with peltier plate, constant 10 Pa shear stress, 2° C./min temperature ramp from 0° C. to 100° C.  
   
   
       10 . A process for stabilizing a polyolefin against the deleterious effects of melt processing, heat aging and exposure to combustion products of natural gas, which process comprises 
 incorporating into or applying to said polyolefin    an effective stabilizing amount of one or more compounds of the formula I or II according to  claim 1 .    
   
   
       11 . A process according to  claim 10  comprising incorporating or applying one or more compounds of the formula I.  
   
   
       12 . A process according to  claim 10  comprising incorporating or applying one or more compounds of the formula II.  
   
   
       13 . A process according to  claim 10  where the compounds of formula I or II are incorporated or applied at a level of from about 0.01% to about 5% by weight, based on the weight of the polyolefin.  
   
   
       14 . A process according to  claim 10  where the compounds of formula I or II are incorporated or applied at a level of less than about 3% by weight, based on the weight of the polyolefin.  
   
   
       15 . A process according to  claim 10  comprising incorporating or applying a further stabilizer selected from the group consisting of hindered phenolic antioxidants, hydroxylamines, benzofuranones, other organic phosphorus stabilizers, sterically hindered amine light stabilizers and hydroxyphenylbenzotriazole, tris-aryl-s-triazine or hydroxyphenylbenzophenone ultraviolet light stabilizers.  
   
   
       16 . A process according to  claim 10  where the polyolefin is polyethylene.  
   
   
       17 . A process according to  claim 10  where the polyolefin is low density polyethylene.  
   
   
       18 . A polyolefin composition stabilized against the deleterious effects of melt processing, heat aging and exposure to combustion products of natural gas, which composition comprises 
 a polyolefin and    an effective stabilizing amount of    one or more compounds of the formula I or II according to  claim 1.